Opthalmic compositions for inhibiting clouding of the ocular lens

ABSTRACT

Compositions containing an oxysterol or a precursor thereof and a cyclodextrin and methods for use of these compositions in inhibiting or preventing formation of crystallin proteins in the lens of the eye thereby inhibiting clouding or increasing clarity of the eye lens are provided.

This patent application claims the benefit of priority from U.S.Provisional Application Ser. No. 62/942,474, filed Dec. 2, 2019 and U.S.Provisional Application Ser. No. 62/848,750, filed May 16, 2019, thecontents of each of which are herein incorporated by reference in theirentireties.

FIELD

This disclosure relates to compositions containing an oxysterol or aprecursor thereof and a cyclodextrin and methods for use of thesecompositions in inhibiting or preventing formation of crystallinproteins in the lens of the eye thereby inhibiting clouding and/orincreasing clarity of the eye lens.

BACKGROUND

The lens of the eye is an important part of the dioptric system. Thelens is a transparent, biconvex structure in the eye that, along withthe cornea, helps to refract light to be focused on the retina. Anyopacity or clouding of the lens of the eye leads to an overall reductionin eye health and vision.

Traditionally recognized treatment for clouding of the lens which occursin cataracts is surgery. Cataract surgery often requires the lens of theeye to be removed and replaced with an artificial lens. However, thisprocedure is both costly and requires recovery time.

The paradigm that cataracts are irreversible and that vision fromcataracts can only be restored through surgery has recently beenchallenged by reports that oxysterols such as lanosterol and25-hydroxycholesterol can restore vision by binding to αB-crystallinchaperone protein to dissolve or disaggregate lenticular opacities(Daszynski et al. Sci Rep 2019 9:8459 doi:10.1038/s41598-019-44676-4).However, in in vitro rat lens studies and human lens proteinsolubilization studies, Daszynski et al. showed the compared to ATP,both oxysterols failed to reach the acceptable threshold binding scoresfor good predictive binding to the cffl-crystallins. All studies byDaszynski et al. failed to provide evidence that lanosterol or25-hydroxycholesterol have either anti-cataractogenic activity or bindaggregated lens protein to dissolve cataracts (Sci Rep 2019 9:8459doi:10.1038/s41598-019-44676-4).

There is a need for alternative treatments for ocular lens opacities.

SUMMARY

An aspect of this disclosure relates to a composition comprising anoxysterol or a precursor thereof and a cyclodextrin.

Another aspect of the present invention relates to a method forinhibiting or preventing formation of crystallin proteins in the lens ofthe eye. In this method, a composition comprising an oxysterol or aprecursor thereof and a cyclodextrin is administered topically to theeye so that formation of crystallin proteins in the lens of the eye isprevented or inhibited.

Another aspect of the present invention relates to a method forinhibiting clouding and/or increasing clarity of the ocular lens. Inthis method, a composition comprising an oxysterol or a precursorthereof and a cyclodextrin is administered topically to the eye so thatclouding of the ocular lens is inhibited and/or clarity of the lens isincreased.

Yet another aspect of the present invention relates to a method fortreating cataracts in a subject. In this method, a compositioncomprising an oxysterol or a precursor thereof and a cyclodextrin isadministered topically to the eye of a subject suffering from cataractsso that the cataract is treated.

DETAILED DESCRIPTION

Provided by this disclosure are compositions containing an oxysterol ora precursor thereof and cyclodextrin and methods for their use ininhibiting or preventing formation of crystallin proteins in the lens ofthe eye thereby inhibiting clouding and/or increasing clarity of the eyelens.

Compositions of this disclosure provide a bio-compatible, aqueous,lipid-soluble molecule delivery system for passage of oxysterols throughlipid barriers present in the eye and into the afflicted lens of theeye.

Oxysterols useful in the compositions are capable of reducing thecrystallin protein aggregate that causes cataracts. Examples include butare not limited to lanosterol, dihydrolanosterol, 25-hydroxycholesterol,27-hydroxycholesterol, squalene, and triterpenoids, as well asanalogues, prodrugs or precursors thereof. A nonlimiting example of auseful precursor of lanosterol is dihydrolanosterol. In one nonlimitingembodiment, the composition comprises a mixture of both lanosterol anddihydrolanosterol.

In one nonlimiting embodiment, the oxysterol is present in a range ofbetween 0.01%-2% weight by volume of the aqueous composition.Compositions may include an amount of oxysterol ranging from 1 mm to 250mm concentrations.

Compositions of the present invention further comprise a cyclodextrin.In one nonlimiting embodiment, the cyclodextrin is beta-cyclodextrin oran analogue of beta-cyclodextrin. In one nonlimiting embodiment, thecomposition comprises beta-cyclodextrin and at least one analogue ofbeta-cyclodextrin.

In one nonlimiting embodiment, the cyclodextrin is present in a range ofbetween 15%-25% weight by volume of the aqueous composition.

Without being bound to any particular theory, it is believed that theoxysterol molecule acts as a guest in the host cavity of thecyclodextrin. The formulation results in an equilibrium of freeoxysterol to complexed oxysterol. The resulting composition allows forthe passage of an oxysterol such as lanosterol through lipid barrierspresent in the eye and into the afflicted lens of the eye. As theaqueous solution is biocompatible with eye tissue, the compositions ofthis disclosure provide a distinct advantage over compositionscontaining ethyl alcohols and other non-biocompatible constituents.

The compositions of this disclosure further comprise deionized water andone or more of an emulsifier, a surfactant, a thickening agent, astabilizer, a penetration enhancer, a salt and/or a lubricant.

Nonlimiting examples of penetration enhancers include mineral oils(petrolatum), various glycols such as, but not limited to propyleneglycol, hydroxypropyl guar and ethylene glycol, glycerin and alcoholssuch as ethanol or benzyl alcohol. In addition, surfactants in thecompositions can act as penetration enhancers.

Biocompatible salts or buffers can be used in the compositions tomaintain the osmolarity between 50 and 2000 mOsm/kg with a preferableosmolarity being 300 mOsm/kg. In one nonlimiting embodiment, a 0.6% W/VNaCl concentration is used to facilitate complexing interactions andmaintain osmolarity.

Examples of emulsifiers which can be used include, but are not limitedto, hydroxypropyl-beta-cyclodextrin in addition to the cyclodextrinagent used for complexing, polysorbate-80 and polyacrylic acid, as wellas other emulsifiers known in the art.

Nonlimiting examples of thickening agents or stabilizers include, butare not limited to, carboxymethylcellulose, hydroxypropylmethylcellulose and hydroxy ethyl methyl cellulose as well as othersimilar hygroscopic thickening agents known to the skilled in the art.

For surfactants, a nonionic surfactant is preferred. Nonlimitingexamples of commercially available nonionic surfactants includeKolliphor® P 188, Plurionic P123, Lutrol® F68, Poloxamer 188, andpoly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethyleneglycol) and similar copolymers consisting of ethylene glycol, propyleneglycol, propylene oxide and/or similar hydrocarbon polymers consistingof non-ionic monomers.

Nonlimiting examples of lubricants include glycerin, glycerol, castoroil, carbomer, polysorbate 80, hypromellose, carboxymethylcellulose,sodium hyaluronate, hydroxypropyl-guar, polyvinylpyrrolidone,polyethylene glycol 400 and propylene glycol.

In some nonlimiting embodiments, the compositions further comprise apreservative. In one nonlimiting embodiment, the preservative isincluded in a range between 0.1-0.8% weight by volume. Nonlimitingexamples of preservatives include biocompatible preservatives such asbenzalkonium chloride 0.005% as well as benzyl alcohol.

In addition, in some nonlimiting embodiments, the compositions furthercomprise an antioxidant between 0.1 and 0. 3% weight by volume may beadded.

Nonlimiting examples of antioxidants useful in the compositions of thisdisclosure include N-acetylcarnosine, carotenoids, Vitamin A, Vitamin B,Vitamin C, n-acetylcysteine, erythorbic acid, sodium sulfites, sodiumthiosulfate, thioglycerol, dithiothreitol and dithioerythreitol, as wellas similar biocompatible antioxidants.

Further, in some nonlimiting embodiments, the compositions comprise abuffering agent included for long-term stability. In these nonlimitingembodiments, the buffering agent is included to maintain a biological pHrange of pH 4.5-8.0. A preferred pH for the ophthalmic composition is pH6.2. Nonlimiting examples of buffering agents include citrate buffers,histidine buffers, Tris-HCl, acetate buffers and some phosphate-basedbuffers. Phosphate buffered saline (PBS) is not compatible with theinclusion complexes above pH 6.0. PBS has also been identified as anocular calcification agent. Accordingly, it is preferred thatphosphate-based buffers other than PBS be used in the compositions ofthis disclosure.

Compositions of this disclosure are formulated for administration viatopical application to the eye. Preferred is that the compositions beadministered in the form of eye drops at least once, more preferably atleast twice a day to a subject in need. At each administration, at leasttwo drops are administered to each eye.

Compositions of this disclosure can be administered to inhibit orprevent formation of crystallin proteins in the lens of the eye of asubject. Further, administration of the compositions will inhibitclouding and/or increase clarity of the ocular lens of a subject. Thus,the compositions of this disclosure are useful in treating cataracts andother vision disorders relating to lens clarity in a subject.

Subjects to which the compositions may be administered include anymammal which forms unwanted crystallin proteins in the eye tissue.Examples include, but are in no way limited to, but are not limited to,humans, dogs, cats, horses, rabbits, rodents, cattle, and primates.

In one nonlimiting embodiment, the biocompatible compositions of thisdisclosure are prepared in two steps.

As a nonlimiting example, the first step may involve the formation ofinclusion complexes predominantly of a cyclodextrin such asmethyl-beta-cyclodextrin and an oxysterol such as lanosterol, and to alesser extent a cyclodextrin such as hydroxypropyl-beta-cyclodextrin andan oxysterol such as lanosterol. To form the inclusion complexes,desired amounts of the methyl-beta-cyclodextrin,hydroxypropyl-beta-cyclodextrin and lanosterol are mixed with deionizedwater and then heated to form the precursor solution. The resultantprecursor solution is made of complexed molecules of the oxysterol andcyclodextrin such that the aqueous solubility of the oxysterol moleculesis significantly increased. The quantity ofhydroxypropyl-beta-cyclodextrin may be added in greater quantity thannecessary for complexing to improve complex solubility. Alternatively,the inclusion complexes can be formed by freeze drying or pressurizing asolution of these cyclodextrins and lanosterol after dispersion inwater, ethanol or a similar solvent. The resulting complex formationscan exist either in solution or as a solid before they are added to thebulk of the solution. While not being bound to any particular theory, itis believed that the molar substitution of hydroxypropyl and methylgroups on hydroxypropyl-beta-cyclodextrin and methyl-beta-cyclodextrin,respectively, affect the solubility and enthalpy of inclusion formationof these molecules. Molar substitution must be sufficiently high forprovision of aqueous solubility to each cyclodextrin through theaddition of hydrogen bonds. However, the degree of substitution alsoimpacts the stability of inclusion complexes. Higher degrees ofsubstitution polarize the molecules, thereby limiting their interactionwith nonpolar molecules such as lanosterol. In the compositions of thisdisclosure, it is believed that the combination of highly-substitutedhydroxypropyl-beta-cyclodextrin and low-substitutionmethyl-beta-cyclodextrin uniquely improves the solubility of bothcomponents without sacrificing the stability ofmethyl-beta-cyclodextrin/lanosterol inclusions. With regard toformulation, methyl-beta-cyclodextrin is expected to have a low-moderatedegree of substitution and hydroxypropyl-beta-cyclodextrin is expectedhave a high degree of substitution.

After the precursor solution of inclusion complexes is completelysolubilized and cooled to ambient temperature, in this nonlimitingexample, the precursor solution is then added in the second step to asecond solution to form the biocompatible composition. The secondsolution is comprised of deionized water and one or more of anemulsifier, a surfactant, a thickening agent, a stabilizer, and alubricant. In some nonlimiting embodiments, an antioxidant is also addedto the second solution.

In this nonlimiting example, the resulting biocompatible composition hasa hydroxypropyl-beta-cyclodextrin content of between 15-25% weight byvolume, a methyl-beta-cyclodextrin/lanosterol inclusion complex contentbetween 0.5-5% weight by volume, and a carboxymethylcellulose contentbetween 0.1 and 1.0% weight by volume. Other optional contents of thebiocompatible composition include surfactant between 0.5-2.5% weight byvolume, lubricant between 0.1-3% weight by volume, and stabilizer of0.02% weight by volume.

In another nonlimiting embodiment, the biocompatible composition is madeby combining an aqueous solution (precursor solution) ofmethyl-beta-cyclodextrin inclusion complexes which are added to a secondsolution of hydroxypropyl-beta-cyclodextrin or other emulsifier, notinclusion complexed), non-ionic surfactant, glycerin, thickening agent,stabilizer, and an antioxidant. If desired a preservative may also beincluded in the second solution.

In yet another nonlimiting embodiment, an aqueous composition is formedhaving a precursor compound of lanosterol, hydroxypropyl-3-cyclodextrin,and methyl-β-cyclodextrin (MBCD). In this nonlimiting embodiment, theratio of MBCD to lanosterol is at least a 1:1 MBCD:lanosterol molarratio. Optionally, the solution may further comprise a nonionicsurfactant, hypromellose USP or glycerin. In this nonlimitingembodiment, hydroxypropyl-β-cyclodextrin is present in a range of 1%-50%weight by volume and methyl-β-cyclodextrin is present in a range of0.05%-30% weight by volume. When the nonionic surfactant is present, itis typical to have between 0.001%-4% weight by volume. When hypromelloseUSP is present it is in a range of 0.01%-5% weight by volume. Whenglycerin is present, it is in a range of 0.01-5% weight by volume.

In yet another nonlimiting embodiment, an aqueous composition is formedhaving a precursor compound of lanosterol, hydroxypropyl-β-cyclodextrin,methyl-β-cyclodextrin (MBCD), a nonionic surfactant at 1% weight byvolume, a lubricant such as glycerin USP at 1% weight by volume, carboxymethyl cellulose USP at 0.3% weight by volume, and a preservative suchas benzyl alcohol USP at 0.3% weight by volume. In this nonlimitingembodiment, lanosterol is present in a range of 0.1% to 1.0% by weightby volume, and preferably between 0.15 and 0.35% weight by volume;hydroxypropyl-β-cyclodextrin is present in a range between 1%-50% weightby volume; methyl-β-cyclodextrin is present in a range between 0.1%-30%weight by volume; and a nonionic surfactant is present in a rangebetween 0.1% and 2% weight by volume. In this nonlimiting embodiment, anantioxidant such as N-acetyl carnosine can further be added to theformulation. The N-acetylcarnosine, if added, is present in a rangebetween 0.25% and 3% weight by volume. Hypromellose USP can also beadded in a range of 0.01%-5% weight by volume as well as a preservativesuch as benzalkonium chloride in a range of 0.001% to 0.05% weight byvolume.

The following nonlimiting examples are provided to further illustratethe present invention.

EXAMPLES Example 1: Preparation of Composition

An aqueous solution was prepared in two steps. The first step involvedpreparation of inclusion complexes where 72 g ofmethyl-beta-cyclodextrin (molar substitution 0.6 or higher), 180 ghydroxypropyl-beta-cyclodextrin and 14 grams of lanosterol were mixedwith 240 ml of deionized water in a sealed container. The mixture washeated to 90° C. for 6 hours and pressurized to 1100 Torr. The mixturewas cooled to ambient temperature slowly for at least 1 hour and thendeionized water was added such that the total volume was 800 ml. The pHwas adjusted to pH 6.5 through the titration of HCl.

The 800 ml solution of methyl-beta-cyclodextrin inclusion complexes wasthen added to a 3.2 L solution including the emulsifierhydroxypropyl-beta-cyclodextrin, the non-ionic surfactant Kolliphor P188, glycerin as a lubricant, benzyl alcohol as a preservative,carboxymethylcellulose as a thickening agent, polysorbate 80 as astabilizer, and N-acetylcarnosine as an antioxidant. The resultingsolution had the final concentration of 22.0% weight by volume ofhydroxypropyl-beta-cyclodextrin, 2.15% weight by volume ofmethyl-beta-cyclodextrin/lanosterol inclusion complex, 0.1% weight byvolume of carboxymethylcellulose, 1% weight by volume of Kolliphor P188, 1% weight by volume of N-acetylcarnosine, 1% weight by volume ofglycerin, 0.3% weight by volume of benzyl alcohol and 0.02% weight byvolume of polysorbate.

Example 2: Administration of Composition

A canine subject with cataracts was administered the composition ofExample 1 over a 131 day period. The subject received twice dailyadministrations of the 25 mm lanosterol solution of at least 2 drops pereye for a total of 4 drops per eye per day. The subject was continuouslyobserved to monitor lens opacity, responsiveness and behavior.Continuous application of the composition to the lens of the subject ledto improved light responsiveness, increased lens clarity and increasedresponse to distant stimuli.

What is claimed:
 1. A composition comprising an oxysterol or a precursorthereof and one or more cyclodextrins in aqueous solution.
 2. Thecomposition of claim 1 wherein the oxysterol is lanosterol.
 3. Thecomposition of claim 1 comprising lanosterol and dihydrolanosterol. 4.The composition of claim 1 wherein the oxysterol is present in a rangeof between 0.01%-2% weight by volume of the composition.
 5. Thecomposition of claim 1 wherein the cyclodextrin is a beta-cyclodextrinor an analogue thereof.
 6. The composition of claim 1 comprising amixture of methyl-beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin.7. The composition of claim 1 further comprising one or more of anemulsifier, a surfactant, a thickening agent, a stabilizer, a lubricant,a penetration enhancer or a salt.
 8. The composition of claim 1formulated for topical administration via drops to an eye.
 9. A methodfor inhibiting or preventing formation of crystallin proteins in anocular lens of a subject, said method comprising administering thecomposition of claim 1 to an eye of the subject.
 10. The method of claim9 wherein the composition is administered topically.
 11. A method forinhibiting clouding and/or increasing clarity of an ocular lens of asubject, said method comprising administering the composition of claim 1to an eye of the subject.
 12. The method of claim 11 wherein thecomposition is administered topically.
 13. A method for treatingcataracts in a subject, said method comprising administering thecomposition of claim 1 to an eye of the subject.
 14. The method of claim13 wherein the composition is administered topically.